除了在一列中具有非唯一值的行之外，抓取表中的所有行列

Question

I understand that if I use something like: SELECT DISTINCT product_id FROM products;

It will return the product_id column with unique values. However if I want to return the other columns from the table as well, is DISTINCT still the best approach?

Or is a group by statement more appropriate?

(I'm using Postgres)

Answer 1

SELECT DISTINCT ON (product_id) * FROM products

That will return rows with distinct product_id , and return all columns of those rows.

If you care about the data in those other columns (eg you want the latest row for each product_id, rather than just random rows), you should also include an order:

SELECT DISTINCT ON (product_id) * FROM products ORDER BY product_id, [other fields]